Core-multishell lanthanide-doped nanocomposite by one-pot synthesis for NIR-II emissions-based temperature sensing

The performances of nanothermometers based on visible light are inevitably degraded in biological applications because visible light is greatly weakened after passing through tissues. Herein, in view of the second biological optical transparency window, a type of tailored core-multishell lanthanide-doped nanocomposite was synthesized with facile one-pot coprecipitation method to supplant complex method demanding stepwise thermal decomposition. Proved to have excellent dispersibility, crystallinity, stability and luminous efficiency, the nanocomposite is capable of enhanced NIR-II emissions and a broad temperature detection scope based on three kinds of spectral parameters relevant to its unique core-multishell structure. The maximum absolute and relative sensitivity of luminescence intensity ratios in low temperature range can reach up to 11.3% K−1 and 1.27% K−1, respectively, and a theoretical derivation is provided to address the peculiar V-shaped trend of NIR-II luminescence lifetime. The prepared nanocomposite can serve as a promising candidate for optical thermometer in the fields of cryoablation of diseased tissues and industrial applications in strong magnetic or radiofrequency fields. •Facile one-pot synthesis of uniform and stable core-multishell nanocomposite.•Outstanding cryogenic sensitivity of efficient NIR-II luminescence.•Theoretical derivation expounding V-shaped trend of NIR-II luminescence lifetime.•Great potential for industrial cryogenic detection and in vivo diagnosis.